submodules: update clippy from 3710ec59 to ad3269c4

[matthiaskrgr]

Changes:

Rustfmt all the things
Clippy dogfood
Update for compiletest changes
Use symbols instead of strings
Rustup to rustc 1.36.0-nightly (1764b2972 2019-05-12)
Add regression test for identity_conversion FP
UI test cleanup: Extract many_single_char_names tests
Add tests for empty_loop lint
Add in_macro again
Rename in_macro to in_macro_or_desugar

r? @oli-obk

[rust-highfive]

⚠️Warning⚠️

• These commits modify submodules.

[oli-obk]

@bors r+ p=1

[bors]

📌 Commit 41184aa has been approved by oli-obk

[ehuss]

After this PR, rls's tests seem to fail with an ICE in rustc:

backtrace

thread 'rustc' panicked at 'index out of bounds: the len is 2 but the index is 4294954756', /rustc/a9ec99f4201ec33026a468ef1289f98a95b4d71a/src/libcore/slice/mod.rs:2689:10
stack backtrace:
0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
1: std::sys_common::backtrace::_print
2: std::panicking::default_hook::{{closure}}
3: std::panicking::default_hook
4: rustc::util::common::panic_hook
5: std::panicking::rust_panic_with_hook
6: std::panicking::continue_panic_fmt
7: rust_begin_unwind
8: core::panicking::panic_fmt
9: core::panicking::panic_bounds_check
10: scoped_tls::ScopedKey::with
11: syntax_pos::symbol::Symbol::as_str
12: clippy_lints::utils::match_def_path::{{closure}}
at /Users/eric/.cargo/git/checkouts/rust-clippy-4b72815e96774b3d/ad3269c/clippy_lints/src/utils/mod.rs:1122
13: ::eq
at /rustc/a9ec99f4201ec33026a468ef1289f98a95b4d71a/src/libcore/iter/adapters/mod.rs:589
14: clippy_lints::utils::conf::helpers::doc_valid_idents::{{closure}}
at /rustc/a9ec99f4201ec33026a468ef1289f98a95b4d71a/src/libcore/slice/mod.rs:3153
15: ::eq
at /rustc/a9ec99f4201ec33026a468ef1289f98a95b4d71a/src/libcore/iter/adapters/mod.rs:589
16: std::sys_common::poison::Flag::borrow
at /rustc/a9ec99f4201ec33026a468ef1289f98a95b4d71a/src/libcore/iter/traits/iterator.rs:604
17: ::drop
at /rustc/a9ec99f4201ec33026a468ef1289f98a95b4d71a/src/liballoc/vec.rs:1862
18: ::drop
at /rustc/a9ec99f4201ec33026a468ef1289f98a95b4d71a/src/liballoc/vec.rs:1845
19: ::drop
at /rustc/a9ec99f4201ec33026a468ef1289f98a95b4d71a/src/liballoc/vec.rs:1731
20: std::sys_common::poison::Flag::borrow
at /rustc/a9ec99f4201ec33026a468ef1289f98a95b4d71a/src/libcore/iter/traits/iterator.rs:1465
21: clippy_lints::utils::match_def_path
at /Users/eric/.cargo/git/checkouts/rust-clippy-4b72815e96774b3d/ad3269c/clippy_lints/src/utils/mod.rs:1122
22: ::check_block_post::{{closure}}
at /Users/eric/.cargo/git/checkouts/rust-clippy-4b72815e96774b3d/ad3269c/clippy_lints/src/regex.rs:116
23: ::check_expr
24: as rustc::hir::intravisit::Visitor>::visit_expr
25: rustc::hir::intravisit::walk_expr
26: as rustc::hir::intravisit::Visitor>::visit_expr
27: rustc::hir::intravisit::walk_fn
28: rustc::hir::intravisit::walk_item
29: rustc::hir::intravisit::Visitor::visit_nested_item
30: rustc::hir::intravisit::walk_crate
31: rustc::lint::context::late_lint_pass_crate
32: rustc::lint::context::late_lint_crate
33: rustc::util::common::time
34: rustc::util::common::time
35: __rust_maybe_catch_panic
36: as core::ops::function::FnOnce<()>>::call_once
37: __rust_maybe_catch_panic
38: rustc_interface::passes::analysis::{{closure}}
39: rustc::util::common::time
40: rustc_interface::passes::analysis
41: rustc::ty::query::__query_compute::analysis
42: rustc::ty::query::::compute
43: rustc::dep_graph::graph::DepGraph::with_task_impl
44: rustc::ty::query::plumbing::::get_query
45: rustc::ty::context::tls::enter_global
46: rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}
47: rustc_interface::passes::create_global_ctxt::{{closure}}
48: rustc_interface::interface::run_compiler_in_existing_thread_pool
49: std::thread::local::LocalKey::with
50: scoped_tls::ScopedKey::set
51: syntax::with_globals

Is there anyone around who can help me debug it? For context, I would like to update cargo before beta, which will require updating rls, which will require getting rls working. cc @Xanewok

Also cc @Manishearth who looks like did the PR to update Symbol handling in clippy. There something fishy with the getting the interned string for a Symbol. I know very little about clippy, rustc, and rls, so I don't think I'll be able to make much progress.

Reproducing is fairly easy. Check out rls, change the clippy hash in Cargo.toml to the latest clippy, build with latest nightly. Create a cargo project with an empty lib.rs, and main.rs with fn main() {}. Run rls --cli, and it should crash with the above stack trace inside clippy match_def_path.

[Manishearth]

cc @oli-obk , i didn't really do that part of the PR (just the mechanical bits)

[Manishearth]

The backtrace doesn't make sense, there are no expressions in fn main() {}.

It's possible that the Symbol stuff broke some assumptions in RLS as well, and they need to update that.

[ehuss]

(Sorry for the noise on this PR, I'm not sure where to move this discussion.)

Looking closer, I think I see what's wrong. Clippy is storing Symbol definitions in globals (lazy_static), but those symbol definitions are only valid for a single session/thread. When rls fires up a second build, clippy reuses those Symbol definitions, but they point to invalid values.

I'm not sure of the best way to fix that. I'm pretty sure Clippy shouldn't be holding any global references to Symbols. Maybe clippy_lints/src/utils/paths.rs could go back to using strs and create Symbols as needed? I'm not sure how much of a performance issue that would be, or if there's a better way.

I'm going to stop looking for now. Feel free to ping me here or on discord if you have any questions. It looks pretty straightforward, though.

[Manishearth]

That's going to be super inefficient. The long term solution for paths.rs is to move as many of those into "diagnostic items" as possible.

Feels like a bug in libsyntax if this can be done safely, though